Agriculture Reference
In-Depth Information
MacVicar et al. (1965) pointed out that Ñoutside the sugar industry and apart from soil surveys
for irrigation purposes, hardly any progress was made with systematic soil survey and classiÝ-
cation between 1941 and 1958Ò in South Africa.
DEVELOPMENT OF “SOIL CLASSIFICATION: A BINOMIAL SYSTEM
FOR SOUTH AFRICA”
In 1958, the Natal Town and Regional Planning Commission initiated a number of natural
resource surveys of the Tugela River catchment, including a systematic reconnaissance soil
survey, to serve as a basis for sound regional planning (MacVicar et al.
1965). The survey was
completed in 1962 (MacVicar, 1978), and a comprehensive outline of the soil studies conducted
during the survey, including the soil classiÝcation system that was developed, was published in
1969 (Van der Eyk et al., 1969). In the process, provisional deÝnitions of soil series were
developed by De Villiers (1962) and MacVicar (1962). MacVicar et al. (1965) pointed out that
the Tugela basin survey Ñwas the Ýrst systematic soil survey executed in South Africa using
modern concepts of series deÝnition and classiÝcation.Ò
The Tugela basin survey and an upsurge in soil surveying in various other parts of South
Africa coincided with the publication of the 7
,
Approximation (Soil Survey Staff, 1960), which
brought a new dimension and new interest in soil classiÝcation worldwide. The possibility to
use the 7
th
Approximation as a means to classify South AfricaÔs soil series was considered very
strongly (MacVicar, 1978). South Africa had only a small number of soil scientists, and any
classiÝcation had to be easy to use by nonsoil scientists if it was to have any practical value. It
was believed that the 7
th
with its Ñstrange nomenclature,Ò would not be generally
accepted (MacVicar, 1978). I have always believed that this notion that the
Approximation
,
th
Approximation
and later Soil Taxonomy (Soil Survey Staff, 1975; 1999) had a strange or difÝcult nomenclature
is unfounded and unfair. It is very simple and easy to use by teaching oneself to break up the
name of a soil into its small individual pieces, and to look at what each little piece tells you
about the soil. After analyzing the name of the soil in this way, you can then ÑsynthesizeÒ the
soil to get a very clear picture of the actual properties and characteristics of the soil.
The other reason given by MacVicar (1978) for not using the 7
7
th
Approximation is valid,
namely, that it often separated soils that local soil scientists (for good reasons) wanted in one
class into different classes, or, conversely, grouped soils together that local soil scientists wanted
in separate classes. The most important reason why the
th
Approximation could not be usedÐthat
it does not cater to a number of our most important soilsÐis not listed by MacVicar. This is
also true for Soil Taxonomy and the FAO system, as will be pointed out later.
The 7
7
th
Approximation did have a very positive effect on soil classiÝcation in South Africa,
however, for the following reasons:
th
1.
It stimulated new interest in systematic taxonomic soil classiÝcation.
2.
It emphasized that soil attributes should be used to classify soils.
3.
It established the principle of using well-deÝned diagnostic horizons as the key building blocks
for soil classiÝcation.
Points 2 and 3 became cornerstones of the South African soil classiÝcation system that was
developed from about 1960 onward.
During reconnaissance soil surveys in the then Eastern Transvaal Highveld (now called the
Mpumalanga Highveld) by AOC, the soil scientists were Ñconfronted with the problem of
conveying to their clients the nature of the very large number of soils in this areaÒ (MacVicar,
1978). This led MacVicar and Loxton to group the soil series into soil forms, each form having
